A novel integrated time-resolved array avalanche photodiode detection system for nuclear resonant scattering measurements.

The nuclear resonant scattering (NRS) experiment requires photon-counting detectors with high time resolution, short dead time, large dynamic range, low noise, and large detection area. An 8-channel avalanche photodiode (APD) array detector system with high integrity, flexibility, and reliability has been developed to adapt to the demands of NRS experiments. The detector system mainly consists of four key parts: (i) an array-APD sensor, (ii) 8-channel integrated fast preamplifiers, (iii) the time-to-digital converter readout electronics, and (iv) a data acquisition system and EPICS support software. Remarkably, the system exhibits a time resolution of better than 500 ps and has a sufficiently low noise level, allowing for the lowest detection energy threshold of 4 keV. The performance of the new array-APD system as well as its real application in nuclear forward scattering (NFS) and nuclear resonant inelastic x-ray scattering (NRIXS) experiments was tested in two synchrotron facilities. With the new system, the NFS signal very close to the prompt electronic scattering signal can be extracted. Thanks to the customized EPICS-areaDetector-based control software, NRIXS spectra can be readily measured with time and energy information of the NRIXS signal stored in the raw data, which is promising for developing NRIXS data analysis in the time domain. The array-APD detector can be deployed for nuclear resonant scattering experiments at various synchrotron radiation facilities.

Laser defined and driven bio-inspired soft robots toward complex motion control.

The design and actuation of soft robots are targeted at extreme motion control as well as high functionalization. In spite of robot construction optimized by bio-concepts, its motion system is still hindered by multiple actuator assembly and reprogrammable control for complex motions. Herein, our recent work is summarized and an all-light solution is proposed and demonstrated using graphene-oxide-based soft robots. It will be shown that, with a highly localized light field, lasers can define actuators precisely to form "joints" and facilitate efficient energy storage and release to realize genuine complex motions.

Bioinspired Superhydrophobic Surfaces via Laser-Structuring.

Bioinspired superhydrophobic surfaces are an artificial functional surface that mainly extracts morphological designs from natural organisms. In both laboratory research and industry, there is a need to develop ways of giving large-area surfaces water repellence. Currently, surface modification methods are subject to many challenging requirements such as a need for chemical-free treatment or high surface roughness. Laser micro-nanofabrications are a potential way of addressing these challenges, as they involve non-contact processing and outstanding patterning ability. This review briefly discusses multiple laser patterning methods, which could be used for surface structuring toward creating superhydrophobic surfaces.

Surface nanostructuring via femtosecond lasers.

Periodical structures induced by pulsed lasers are a unique phenomenon when pulsed lasers irradiate on some material surfaces. These periodical structures with a subwavelength-scale period hold potential in integrated-optics and biomimetic micro-nanodevices for their direct shaping by laser pulses. However, the blurred nature of the laser-induced structuring hinders its further exploration in these application scopes. In this review, the plasmon-mediated structuring targeted on various materials, both organic and inorganic, will be discussed profoundly.

Six new diterpenoids from Croton laevigatus.

Six new ent-labdane-type diterpeniods (1‒6), along with one known compound, were identified from the twigs and leaves of Croton laevigatus. Their structures were elucidated on the basis of extensive spectroscopic interpretation. Compounds 2 and 7 showed inhibitory activity against protein tyrosine phosphatase 1B (PTP1B) with IC50 values of 4.11 and 8.33 µg/ml, respectively.

Atomic layer deposition for nanofabrication and interface engineering.

Atomic layer deposition (ALD) provides a tool for conformal coating on high aspect-ratio nanostructures with excellent uniformity. It has become a technique for both template-directed nanofabrications and engineering of surface properties. This Feature Article highlights the application of ALD in selected fields including photonics, SERS and energy materials. Specifically, the topics include fabrication of plasmonic nanostructures for the SERS applications, fabrication of 3-D nanoarchitectured photoanodes for solar energy conversions (dye-sensitized solar cells and photoelectrochemical cells), and coating of electrodes to enhance the cyclic stability and thus device life span of batteries. Dielectric coating for tailoring optical properties of semiconductor nanostructures is also discussed as exemplified by ZnO nanowires. Future direction of ALD in these applications is discussed at the end.

Highly effective SERS substrates based on an atomic-layer-deposition-tailored nanorod array scaffold.

When two metallic surfaces supporting plasmonic excitation are brought into close proximity of each other, a nanogap (of width on the subwavelength scale) will form, which boosts greatly the local optical field. Based on this idea, we fabricated two types of three-dimensional plasmonic substrates with such nanogaps, taking advantage of both atomic layer deposition (ALD) and the capillary effect. Owing to the counteraction of the gap-reducing and capillary, nanogaps with different widths and profiles have been formed on the scaffold of aligned ZnO nanorods and shown to induce large field enhancement with enhancement factor up to 2.64 × 10(6) for surface-enhanced Raman scattering (SERS).